Los Angeles — Comedian Mort Sahl once called Los Angeles “100 suburbs in search of a city.” As the nation’s second largest metropolis votes for a new mayor Tuesday, it is also in search of a clear winner.

Two Democrats – former City Controller Wendy Greuel and former City Council President Eric Garcetti, are in a dead heat, vying for the top post. Voter turnout is expected to be low – though an extra push by both candidates for the absentee ballot nod is expected to help the numbers from falling to historic lows.

All in all, “this is a diffuse race with no clear front-runner,” says Sherry Bebitch Jeffe, a senior fellow at the School of Policy, Planning, and Development at the University of Southern California.

Beyond the general voter apathy that bedevils many local races, Los Angeles politics also suffers from the city's far-flung geography, which breeds a disconnect between City Hall and the city’s nearly 4 million residents. “City Hall is downtown and far away from most neighborhoods,” says Ms. Jeffe. “Potholes and issues like that are what get attention, not the mayor’s race.”

People turn out to vote when they think that the outcome will make a big difference, agrees Jack Pitney, professor of government at Claremont McKenna College in Claremont, Calif. In this case, he points out that people don't see much daylight between the two candidates. “Both are progressive Democrats with ties to labor unions,” he says via e-mail, albeit different unions.

The issue of pension-fund liabilities looms large over any California city because cities are on the hook for unmet pension payments to retirees. But, “either will have a hard time meeting the city's pension obligations,” he says. “Neither can repeal arithmetic.”

Because of the way the Los Angeles city government is structured, compared with other cities, the mayor is not a particularly powerful figure, says Jessica Levinson, a professor at Loyola Law School in Los Angeles. Nonetheless, the city has an $8 billion budget, and the mayor is a national figure.

Other items on the ballot can often help to drive voters to the polls, but in this case, “the down-ballot races have failed to capture the public's attention,” says Ms. Levinson via e-mail. There are three ballot measures dealing with medical marijuana and are somewhat overlapping and confusing, she notes. “Only a few people go to the polls just to weigh in on medical marijuana.”

Beyond the issues, for many voters it feels like the November elections weren't that long ago, and local elections not tied to statewide elections generally get dismal voter turnout, Levinson says. “Some people are not aware of the fact that there is an election today.”

The people who do turnout Tuesday will be those who rarely miss an election or feel strongly about the mayoral candidates or medical marijuana, she says. “We can expect to see few more than the particularly civic-minded show up to the polls today.”

What that means is that the predominantly white, older, educated resident is expected to drive results in the mayor’s race, Jeffe says. Both candidates have made strong pitches for the Latino vote, reaching out to local leaders. But neither the private nor the public polls have come up with any definitive answers, Jeffe adds.

If the internal polls each side conducts had come up with a clear advantage, “you better believe they would be trumpeting those numbers." But, she adds, “they are not, so it’s anybody’s guess who will win tonight.”